The present invention relates generally to railway couplers and, more particularly, to a rotary railway drawbar coupler.
Railway cars, especially freight cars, are connected by various means. One connection method is the rather well known use of independent coupler units which extend from either end of each railway car. Such coupler units most typically comprise a shank portion which extends into the railway car sill and is secured therein, with the coupler head extending outwardly from the railway car. Such coupler heads are usually referred to as automatic couplers and are adapted to connect to a similar coupler head protruding from another railway car.
Another method of connecting railway freight cars is the use of an integral drawbar one end of which would extend into a railway car sill to be secured therein, and the other end of which would extend into another railway car sill to be secured therein thereby coupling the two railway cars. Such drawbar couplers, or more simply drawbars, have the advantage over independent couplers of being lighter in weight, an important consideration in overall freight train fuel efficiency.
In certain freight car applications, it is desirable to be able to rotate one freight car while such car remains coupled to the adjoining cars in the freight train. Most typically, such rotary capability is desirable for freight gondola cars to unload coal or other solid granular material therefrom. The traditional drawbar coupler described above would not accommodate such car rotation. Such drawbars are set forth in U.S. Pat. No. 4,456,133, assigned to the assignee of the present invention.